The primary objective of the proposed study is to evaluate the marginal effects of introducing two levels of environmental interventions directed at reducing overweight and obesity in the workplace, on top of existing individualized interventions, on five sets of outcomes: a. body mass index and other weight-related biometric measures; b) behavioral health risk factors; c) weight-related health conditions; d) health care utilization and medical expenditures; and e. employee productivity measured in terms of reduced absenteeism and on-the job presenteeism. The design also includes an assessment of costs and benefits of the two treatments, considering the medical, absenteeism and productivity benefits derived from such interventions, an assessment of the impact of the interventions on the worksite climate. We propose a quasi-experimental design that is appropriate for the nature of the intervention. Six manufacturing locations in Louisiana and Texas operated by The Dow Chemical Company, employing 6,000 workers will serve as study sites. They will be randomly assigned to a moderate environmental treatment, an intensive environmental treatment, or control (individualized treatment only). The moderate interventions will include inexpensive environmental changes (e.g., prompts and reminders), while the high intensity intervention will involve engagement of senior managers in development of a worksite culture that is broadly supportive of improved weight and health management by employees. Annual health screening and biometrics data along with administrative medical claims, absence records, and productivity survey data will be analyzed to determine program impacts. Non-experimental statistical methods will be used to control for baseline differences that remain across sites after randomization. The study will also produce extensive information about how employers can successfully implement environmental treatments at worksites.